The reason, according to the board's editorial, is that the Republican nominee is "unfit for the presidency."

The board unanimously agreed that Trump should not be elected, though it was not unanimous on recommending Democrat Hillary Clinton. The board, therefore, urged Americans to "Stay true to your convictions," whether that means voting for Clinton, a third-party candidate, a write-in or simply focusing on down-ballot races.

"Whatever you do, however, resist the siren song of a dangerous demagogue," the board wrote. "By all means vote, just not for Donald Trump."

The board cited Trump's refusal to release his tax returns, his cozying up to Russian President Vladimir Putin, and his hinting that he might not keep commitments to NATO among its reasons.

In an accompanying story explaining why it has decided to break with tradition in recommending against voting for Trump, the board cited the paper's founder Al Neuharth, who like Trump had a big ego.

In a 2012 column, the year before his death, Neuharth, called Trump "a clown who loves doing or saying things" to get attention, "no matter how ridiculous."